1. Field of the Invention
The invention is directed to apparatus for aiding in the off-loading of bulk raw materials, particularly solid resins, or materials for making solid resins, from a railroad hopper car.
2. Description of Related Art
It is often necessary to off-load bulk raw materials such as solid resins, materials for making solid resins, wheat, flour, etc., from a railroad hopper car into a receptacle such as a silo or other storage container. This is usually done by connecting a flexible hose to an outlet of the hopper car (which outlet is standard equipment and has been incorporated for that purpose) and emptying the hopper car of its contents. It will be appreciated that for materials which pose a threat for explosion, the hoses/conduits used for off-loading are preferably pressurized by an inert gas, such as dry nitrogen, to ensure that oxygen does not enter the system. For materials which do not pose an explosion problem, ambient air may be used. As shown in FIG. 1, which is a greatly simplified schematic of a typical setup for such a prior art transfer operation, a flexible metal hose 11 is connected to the outlet of a hopper car 10 fitting 20 (shown in more detail in FIGS. 2A and 2B). For simplicity, the return air path and associated hardware are not shown or discussed at this point. The hose 11 is, in turn, connected to the inlet side of a blower 12 either directly or by intermediate tubing 11a. It will be appreciated that the blower is usually placed in the "return" air line. The outlet of blower 12 is connected by outlet tubing 11b to the top of a silo 14. When it is desired to off-load the cargo from hopper car 10, a valve (not shown) operated by handle 23 at the hopper car 10 outlet fitting 20 (see FIG. 2A) is opened and the blower 12 is energized thereby forcing the gaseous transporting fluid (and cargo) through the tubing 11, 11a, 11b. The raw material is thus withdrawn from the hopper car 10 through outlet fitting 20, and transported into the silo 14 in a manner which is well known to those skilled in the art.
FIG. 2A shows a typical hopper car 10 outlet fitting generally designated at 20 which is standard equipment on hopper cars. Generally, there are two such fittings located on opposing sides of each compartment of a hopper car 10, one (an inlet 20a) for supplying a fluidizing medium such as air/nitrogen, and one (an outlet 20) for removing the raw material from the hopper car 10. For ease of illustration, only the outlet side fitting 20 is described in detail since they are interchangeable. The outlet fitting 20 (shown in more detail in FIG. 2B ) comprises a trough tube 21 which is press-fit into a collar 22 which is, in turn, permanently affixed to the hopper car 10. A handle 23 is readily accessible for opening and closing a valve (not shown) connected thereto and which, in its open position, allows the outflow of material from the hopper car 10 and through the hose 11.
An adapter was required to connect the hose 11 to the outlet fitting 20. A typical prior art adapter previously used by Assignee herein is shown in FIGS. 3A, 3B wherein a rubber slip tube adapter 30 is installed around the trough tube 21 of the hopper car 10 outlet fitting 20. The rubber slip tube adapter 30 may be, e.g., a standard 63/4 inch O.D. .times.1/4 inch thick rubber tube. The trough tube 21 is used to adapt the steel flexible "product" hose 11 (FIG. 1) to the outlet fitting 20 of the hopper car 10, FIGS. 2A, 2B. The hose 11 is connected to a blower 12 for the purpose of conveying the bulk product into and through a product-conveying loop comprising conduits 11, 11a, 11b and thence into silo 14 as shown in FIG. 1. The rubber slip tube adapter 30 is secured to the trough tube 21 and hose adapter 19 by tightening the bolts of split clamps 32, 34, thereby compressing and sealing the rubber tube 30 against the trough tube 21 and hose adapter 19. A camlock fitting 31 is provided for mating attachment to hose 11. The trough tube 21, as noted above, is press-fit into the collar 22 (and thereby into hopper outlet fitting 20 itself, as described above) and, due to this press-fit, the slip tube adapter 30 and the trough tube 21 have a tendency to loosen with respect to collar 22 and, in turn, the outlet fitting 20, during the transfer process. The trough tube 21 has been known to completely separate from the hopper outlet 20, thereby causing a breach in the system. This is unsafe, due to the introduction of air into an inerted (such as by dry nitrogen) system which is conveying a dusty powder and because of the exposure of personnel thereto at the time of the release. It also has a negative environmental impact due to the release of product to the environment. Other problems are encountered due to the material of construction, i.e., the slip tube 30 is constructed entirely of a rubber material which is an electrical insulator. This is not desirable because of the need to bond, i.e., to electrically ground the entire system in order to dissipate the electrostatic charge created during the transfer of product, thereby reducing the chance of an explosion. This has heretofore generally necessitated a grounding wire system connecting the hopper car 10 to the downstream transfer system.
The prior art discloses systems which are primarily hopper car 10 product and trough control devices, which would require a complete reconstruction of the hopper car 10 outlet fitting 20 in order to solve the noted problems. In contrast, the hopper car 10 adapter 40, i.e., the invention disclosed herein, can be installed without any modification to the existing design/configuration of hopper cars and addresses issues not identified in existing designs.